The present invention relates generally to agriculture and, more particularly, to a device for moisture measurement in harvesting machines.
To achieve optimal cultivating of crops and dispensing of fertilizers and plant protection agents according to actual requirements, it is important to determine the yield quantities in respective portions of the cultivated area. The measured yield values of the crop material should be as precise as possible to obtain data from these values for the subsequent produce. The yield is calculated from the stream of material in the harvesting machine, which is in turn related to the mass of crop material dried so as to be capable of storage. Precise determination of the moisture content of the crop material is during harvesting to make the yield correction in the correct position. Furthermore, values can be derived from the measured moisture content of the crop material for adjusting components of a harvesting machine. This also requires high precision of the measured values.
A generic device is known from German Patent Application 41 05 857. The device for moisture measurement shown there serves to correct a quantitative measurement determined by a first measuring device, by a moisture measurement determined by a second measuring device. The second measuring device consists of an overflow vessel. More material to be measured is supplied to the second measuring device in a time interval through an opening than can escape through an opening at the bottom. As a result, under normal harvesting conditions, sufficient filling of the measuring device with continuous exchange of the accruing material to be measured is ensured.
Another moisture measuring device is known from U.S. Pat. No. 5,616,851. There, a device is proposed in which a control flap remains in an "open" position for filling the measuring device, until a sensor indicates sufficient filling of the measuring device.
It is a common feature of both measuring devices that they derive an auxiliary stream from the stream of material for measuring purposes and, after measurement has taken place, return the removed quantity of crop material to the main stream of material. Both devices have the drawback that they soil easily, as a result of which the measured quantities and values are inaccurate, and blockages can occur. The sensors cannot be constantly monitored during continuous harvesting work. Therefore, it is possible for inaccurate values to be measured over a longer period of time owing to soiling or blockage of the measuring chamber or moisture sensor. The inaccurate values are unusable for subsequent evaluations. Furthermore, it is often impossible to subsequently determine the moment when the measured values obtained are erroneous. Thus, not only are the erroneous values disregarded, but also values which are actually correct are lost as well. Harvesting is done only once a year in many regions, therefore, such a loss of data results in a considerable setback in the endeavor to create a reliable database for partially plot-specific applications, especially as data losses can re-occur in subsequent years. Erroneous data which is not noticed can have an adverse effect on the farmer's success. For example, subsequent planning of the use of seed, fertilizers and plant protection agents, using erroneous data can lead to serious misallocations. For these reasons, it is important to carry out moisture measurement as accurately as possible and reliably eliminate all possible sources of error.
Accordingly it is a general object of the present invention to overcome one or more of the deficiencies described above. Another object is to improve the device for moisture measurement in harvesting machines.